1. Field of the Invention
The present invention generally relates to aggregation, and relates more particularly to dynamic aggregation for a plurality of protocols.
2. Description of the Related Art
Broadband access technologies such as digital subscriber lines (DSL) enable internet service providers (ISPs) to provide internet services to subscribers over data networks. Rather than deploying their own data networks, ISPs typically lease access to data networks from network access providers (NAPs). A NAP might be, for example, a company that owns fiber optic cables used in data transmission. Thus, there are multiple ISPs providing internet services over one NAP's network, called an intervening network, to thousand of subscribers. As such, it is typically necessary to track which ISP a subscriber subscribes to, or in other words, which ISP “owns” the subscriber.
FIG. 1. illustrates a conventional network topology where multiple ISPs (ISP A 117 and ISP B 118) serve multiple subscribers over a single aggregation network. A subscriber uses subscriber workstation 111 to send a request for internet services from their ISP, for example, ISP A 117. This request is transmitted via DSL modem 113 to an aggregation point called a DSL Access Multiplexer (DLSAM) 103. These devices are used to aggregate multiple DSL lines, and are often located remotely from the access point such as in neighborhoods and around office buildings. The DSLAMs are connected at layer 2 of OSI to a network element referred to here as an “aggregator” 105. The aggregator aggregates connections from multiple DSLAMs, and potentially differentiates subscribers, authorizes and authenticates subscriber's access to the network, and either terminates the subscribers to provide services, or forwards the subscribers to a remote ISP that “owns” the subscriber.
When the subscriber 111 first connects, the aggregator 105 communicates with a Remote Authentication Dial-In User Service (RADIUS) server 107 to dynamically discover which ISP owns the subscriber 111. The RADIUS server 107 maintains a centralized repository of subscriber information including information about the ISP that owns the subscriber 111. The RADIUS server 107 returns the correct ISP information to the aggregator 105, and the aggregator tunnels a connection for the subscriber 111 through the intervening network 101 to the correct ISP. The RADIUS server 107 can provide dynamic mapping of subscribers to ISPs
Where the retail ISP is providing multicast content to its customers, the wholesale-retail provider setup has prevented efficient transport of the multicast content. The wholesale network provider has typically had to send unicast data to the subscribers 111 from the aggregator 105 because of a lack of awareness of the multicast replication state closer to the subscriber. Although some attempts have been made to more efficiently traverse multicast traffic through the various networks, those attempts have assumed greater control and dependencies than are present in a wholesale-retail provider situation.